AUBURN HILLS, Mich. — Michigan State was rebounding and defending with its usual ferociousness, and the Spartans were fighting among themselves on the bench.

The feisty combination is nothing new for Michigan State, which advanced yesterday to the Sweet 16 of the NCAA Tournament for the fifth time in the past six years.

Looking primed by the physicalness of Big Ten play, third-seeded Michigan State pounded out a 70-48 win by pushing around Memphis, which won all 16 of its Conference USA games to earn a No. 6 seed in the Midwest Regional.

Freshman guard Gary Harris scored 16 of his 23 points in the first half for the Spartans (27-8), who finished with 20 more rebounds than the Tigers.Michigan State’s inside duo of Adreian Payne and Derrick Nix combined for 27 points and 18 rebounds, and Nix added drama by getting into a heated argument with teammate Keith Appling during a second-half timeout.

“It was good for us,” Nix said. “I was a little frustrated and just went after him a little bit. It was just a miscommunication.”

The two are actually roommates, and even played together in high school in Detroit. But they threw towels at each other after the senior Nix, 6 feet 9 and 270 pounds, chewed out the 6-1 junior point guard.

“Situations like that happen all the time in the apartment,” Appling said. “It’s nothing serious. We’re all like brothers. We love each other.”

The cause of strife at home?

“He eats up all the snacks,” Appling said.

In January, Payne and teammate Branden Dawson got into a fight at the team’s hotel before a game at Penn State. Police responded, but there were no arrests.

Michigan State won the 2000 national title after Mateen Cleaves and Morris Peterson got into a locker-room altercation at halftime of a tournament game.

“We have a tendency to do that,” coach Tom Izzo said. “I need players to get on players sometimes.”

Michigan State got on Memphis (31-5) early and built a 13-point lead in the first half before the Tigers drew within 32-29 at the break. It was all Spartans after that, however. They shot 59 percent in the second half and held Memphis to 23 percent shooting.

Appling left the game in the second half after his right shoulder popped out of place, just as it did earlier this season.

“It slid back in by itself,” Appling said. “It’s nothing serious. I should be fine.”

He said he has no doubt he will play in the regional semifinals.

If form holds true, the Spartans will also defend and rebound like mad dogs. And they might fight one another a little bit, too.

“It’s all family,” Nix said. “The best comes out of us when we play with emotion. The tournament is about how hard a team plays, and how focused. It’s not about X’s and O’s anymore.”